【作者】 张鑫；

【导师】 封伟；

【作者基本信息】 天津大学 ， 高分子材料科学与工程， 2020， 硕士

【摘要】 新型二维碲化锗（GeTe）材料,具有类石墨烯褶皱结构,p型半导体,相关理论计算表明该材料具有优异的电子和光学性能,但受其自身结构限制,GeTe存在空气中稳定性差的问题,值得进一步的研究和探索。本论文首先通过Material Studio模拟计算了O与GeTe的结合过程,对GeTe的化学稳定性进行了分析。结果表明O原子偏向于与2个Ge原子形成更稳定的Ge-O-Ge的结构,对GeTe晶体结构产生破坏,这是导致二维GeTe在空气中稳定性差的根本原因。然后,本研究采用超声辅助液相剥离方法,分别在氩气和空气中制备了横向尺寸在10μm的Ar-GeTe和O-GeTe纳米片。EDS和XPS测试结果表明在空气中制备的GeTe纳米片含有大量O元素,与计算结果一致。此外,GeTe纳米片展现出优异的光催化性能和循环稳定性,Ar-GeTe的最高光催化产氢速率可达到1.13 mmol?g^-1?h^-1,比O-GeTe纳米片(0.54 mmol?g^-1?h^-1)高109%,这是因为O原子的掺杂使得晶体结构内出现Ge空位,导致费米能级和价带位置均发生偏移,使得光催化产氢性能降低,UV-DRS和XPS-VB的测试结果可以验证这一猜想。最后通过微机械剥离法制备了GeTe纳米片,并基于该材料使用钛金（5nm/60 nm）电极制备了场效应晶体管。电学测试结果表明该器件具有6.4cm²·V^-1·s^-1的载流子迁移率和670的开关电流比,而且该材料与金属电极间存在明显的肖特基势垒,可将其归因于测试环境中氧气对材料的影响。更多还原

【Abstract】 A new type of two-dimensional germanium telluride（GeTe）material with graphene-like wrinkle structure,p-type semiconductor,and related theoretical calculations show that the material has excellent electronic and optical properties,but due to its own structural limitations,GeTe has poor stability in air which is worthy of further research and exploration.In this paper,the combination process of O and GeTe is simulated by Material Studio,and the chemical stability of GeTe is analyzed.The results show that O atoms tend to form a more stable Ge-O-Ge structure with 2 Ge atoms,which damages the GeTe crystal structure,which is the root cause of the poor stability of 2D GeTe in air.Then,in this study,the ultrasonic-assisted liquid phase stripping method was used to prepare Ar-GeTe and O-GeTe nanosheets with a lateral dimension of 10μm in argon and air,respectively.The EDS and XPS test results show that the GeTe nanosheets prepared in air contain a large amount of O elements,which is consistent with the calculation results.In addition,GeTe nanosheets exhibit excellent photocatalytic performance and cycle stability.The highest photocatalytic hydrogen production rate of Ar-GeTe can reach 1.13 mmol?g^-1?h^-1,which is higher than that of O-GeTe nanosheets(0.54 mmol?g^-1?h^-1)109%higher,because the doping of O atoms causes Ge vacancies in the crystal structure,causing the Fermi energy level and the position of the valence band to shift,reducing the performance of photocatalytic hydrogen production.This conjecture can be verified by the results of UV-DRS and XPS-VB.Finally,GeTe nanosheets were prepared by micromechanical exfoliation,and field effect transistors were prepared based on the material using titanium gold（5nm/60 nm）electrodes.The electrical test results show that the device has a carrier mobility of 6.4 cm²·V^-1·s^-1and a switching current ratio of 670,and there is an obvious Schottky barrier between the material and the metal electrode,which can be classified as due to the influence of oxygen on the material in the test environment.更多还原